Processing of coordinate values of points entered in a graph board or the like

ABSTRACT

A method of processing coordinate values of points entered in a tablet, by means of a digital data processing facility wherein a first tablet area is operated as alpha numerical keyboard by correlating discrete points entered with keyboard numbers; a second tablet area is operated as a description and encoding board by correlating discrete points entered therein with arbitrarily selected description codes; a third tablet area is operated as a graph board by storing points thereof entered in the third area in spatial relation corresponding to their spatial relation on the graph board; numbers, description codes and graph board points are correlated by means of an algorithm that operates in dependence of the order of entry of points in the first, second and third areas.

United States Patent m1 Eichen et al.

H lMarch 13, 1973 [75] Inventors: Howard R. Eichen, Fullerton; Robert H. Paulsen, Placentia, both ofCalif.

[73] Assignee: Co-Data Corporation, Fullerton,

Calif.

[22] Filed: June 3,1971

[21] Appl. No.: 149,617

[52] U.S.Cl ..444/l,235/6l PE, 340/1725 [51] Int. Cl ..G06l'15/00 I58] Field ot'Seareh ..340/172.5,337; 178/87;

235/6l PE; 444/1; 197/105 I56] References Cited OTHER PUBLICATIONS Cameron, S. H. et al. Dialog: A Conversational Programming System with a Graphical Orientation, In Comm. A.C.M. l0(6), pp. 349-357, June [967, QA76A8c.

Primary ExaminerMalcolm A. Morrison Assistant Examiner-R. Stephen Dildine, .lr. Attorney-Smyth, Roston & Pavitt [57] ABSTRACT A method of processing coordinate values of points entered in a tablet, by means of a digital data processing facility wherein a first tablet area is operated as alpha numerical keyboard by correlating discrete points entered with keyboard numbers; a second tablet area is operated as a description and em coding board by correlating discrete points entered therein with arbitrarily selected description codes; a third tablet area is operated as a graph board by storing points thereof entered in the third area in spatial relation corresponding to their spatial relation on the graph board; numbers, description codes and graph board points are correlated by means of an algorithm that operates in dependence of the order of entry of points in the first, second and third areas.

23 Claims, 13 Drawing Figures Marni-1r RROC ESSING OF COORDINATE VALUES OF POINTS ENTERED IN A GRAPH BOARD OR THE LIKE The present invention relates to method and system for acquisition of information. More particularly, the invention relates to method and system for processing information produced on basis of a two dimensional digitizer.

Digitizers have been developed in the past using a planar tablet and a pointer; as the pointer points to a particular point on the tablet a pair of X,Y coordinate values are developed and recorded. Such equipment has been used to translate pictorial representation into digital information. The present invention expands the use of such digitizer.

in accordance with the present invention, it is suggested to use encoded overlays on a portion of the tablet, using the remainder as graphic board or plan area for geometric representation.

The overlays are used to qualitatively designate and to quantitatively particularize subject matter illustrated in the plan area. A single tablet area is used, with the digitizer providing only pairs of coordinates of points; subsequent processing interprets these points and provides interrelationship on basis of the relation of such points including their order of presentation. The overlays are to include a keyboard overlay to be placed in a keyboard area of the tablet and to be used for defining "keys" e.g., in form of a pictorial representation of a keyboard. A digital data processing system, such as a stored program, general purpose computer processes the coordinates of any recorded point on the tablet and distinguishes them, first of all, as to the area in which they have been placed (pointed to). The computer contains manifestations in which the coordinate values of a set of points from the keyboard area are about equivalent to the center of delineated key and is associated with digital information of the number represented by the key. Therefore, as the user points to a "key on the keyboard overlay, a pair of coordinate values are generated, which through associate processing are converted, e.g., into a number.

A program is stored in the computer which associates points of geometric significance in the plan area which have been pointed to, with numerical information that have been keyed-in, also by use of the same pointer. The user is, thus, enabled to delineate a drawing when placed in the plan area by pointing to line-defining points therein, and to provide quantitative information for sealing, and, most importantly, he may establish distance relation between points at any desired degree of accuracy by means of the keyboard." By using the same pointer for both types of inputs, his efficiency is greatly enhanced; he does not need a separate real keyboard. The digitizer itself merely accumulates coordinate pairs of points, pointed to by the pointer. The processor distinguishes the significance of the points and correlates their distinctive interpretation.

Another type of overlay used, to be called descriptive overlay, has delineating "keys" or markings analogous to the keyboard" overlay, but these markings have still different significance. The descriptive overlays are placed also on the tablet, but in the so called overlay area thereof. Basically, they have qualitative significance with or without implied quantitative significance and are used to define the object or objects delineated in the plan area. A user points to one of these delineated points" and generates again a pair of coordinate values which the computer associates with particular codes of arbitrarily definiable significance for digitally defining and identifying any object in the plan area, per se identified therein only by points. Within groups of these codes, distinction is made whether additional, descriptive quantitative data are to be included or whether such quantitative values have to be "keyed-in."

Without intending a restriction, the following specific example will be helpful to understand the concept. An architectural drawing may be placed in the plan area of the digitizer tablet, showing floor elevation of a building. A descriptive overlay defines particulars as to the walls" generally, Thus, if the user points first to a marking insert wall" in the descriptive overlay and then to two corner points in the plan area, he defines length and location of the wall. Conversely, two points in the plan area are identified as a wall by pointing to a descriptive overlay marking for that purpose prior to entering the points of the plan area.

Actually, the user generates only three different pairs of coordinates, but the computer interprets the first pair, in the descriptive overlay, as defining a wall" code and the second and third pairs in the plan area are then the end corners of that wall. As part of the initial preparation, a scale has been keyed-in; particularly a particular distance has been delineated by way of two points, and a numerical value has been keyed in as interpretation of that distance. All subsequent coordinate points are calculated with reference to that distance as scale. If subsequent to entering two plan points, the user "keys-in" a number by pointing to the appropriate keyboard overlay keys, the coordinates of one or both plan points are adjusted to reflect the more accurate digital key-in. Within that wall, two additional points may be entered, and by way of the description overlay they are interpretable as window." A subsequent keyed-in number may be qualitatively identified by the qualitative overlay as height of that window, etc.

It follows from the foregoing that the user manipulates the pointing instrument over three areas of the digitizer area or tablet, the plan area, the keyboard overlay area and the descriptor overlay area. As to each area he identifies merely points, but through subsequent processing points in the plan area are given interrelated geometric significance, points in the keyboard area are given immediate numerical significance, and points in the descriptive overlay area are given codes for identifying geometric relations. Thus, a relationship between plan points is definable and qualitatively interpretable by the descriptive overlay and quantitatively particularized by use of the keyboard overlay.

The output proper of the digitizer is a single data stream defining only coordinate pairs; the computer separates them as to the area in which they originated, whereby the order of appearance of coordinate pairs in the stream is of associative significance and is used as such. The computer processes, interprets and analyzes this data stream and associatively assembles identifying codes with numerical information to completely describe the object illustrated in the plan area. That information can then be used in any manner desired. Different elevations can be plotted, materials lists compiled, etc.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed that the invention, the objects and features of the invention and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a block diagram of a system for practicing the method of the invention; FIGS. 10, lb, 1c are schematic representations of particular portions of the storage facility in the systems of FIG. 1;

FIG. 2 is a schematic representation of the graph board used in FIG. I;

FIG. 2a is a schematic example for a descriptor overlay. FIGS. 3a, 3b and 3c, are a flow chart for an input program as executed by a system of FIG. 1;

FIGS. 4, S and 6 are subroutine flow charts; and

FIG. 7 is a block diagram flow chart for a user program.

SYSTEM DESCRIPTION In FIG. 1 is illustrated a system representing by way of example implementation for practicing the method in accordance with the invention. Some parts thereof are shown in greater detail to facilitate orientation. In essence, the invention will be practiced by means of a computer system which comprises a computer 10 and includes the usual processor equipment such as 11. Processor is understood, possibly, in the collective sense in that processor I1 includes the normally provided central processing unit, or CPU for short, as well as input-output processors in case such separate units are provided for. In addition, the computer includes a memory 12, conventionally a core memory, but it may be any convenient random access memory as used in computers today.

These basic units cooperate usually and also in this case with a plurality of peripheral devices, sometimes called input-output equipment, and some of them are shown as far as they are pertinent for practicing the invention is concerned. The peripheral equipment may include a plotter I3, i.e., an XY writer that provides graphic display in response to a data stream supplied to it defining XY coordinates for a pen or the like. The computer system includes, of course, the conventional input-output printer 14 which may be an automatic typewriter, a regular strip printer or the like. These are the usual output devices for establishing an output that is directly useful to a hum an operator.

The system will of course include memory extension devices such as discs and/or tapes, etc., which do not require elaboration in the general sense. It is pertinent for explaining the invention, however, that there is provided a disc unit 15 interfacing with the computer and containing a number of files which, however, are distinguished through software only. A control bus 151 and a data bus 152 provide for the transfer of control information and data respectively between designated portions of the disc file and memory [2 of the computer,

usually under control of the processor therein. Depending upon the particular computer system employed, operation usually requires that data are temporarily stored in a portion of memory 12 and transferred to a disc file or vice versa. As far as software control of these operations is concerned, it will be discussed more fully below, otherwise standard hardware equipment is of course employed. Also, details of the content of the disc files will be discussed more fully below.

As far as input devices are concerned, it is assumed that the computer has the usual card reader 18, primarily for inputting of programs prepared as a stack of cards, and also mode control information is inputted via the card reader. Next, there is a punched tape reader 16 of conventional design and coupled to the computer by means of two busses, there being a control bus 161 for transfer of control information and for entertaining a dialog between the tape readout and the computer, particularly as to stop and go control for paper strip advance in response to computer issued commands. The data bus 162 provides a flow of data, unidirectionally from tape reader 16 to the computer.

The punched tape serves merely as a link to an input device that prepares the tape so as to obviate the need for on-line operation via a link; also a permanent record of the input operation is provided therein. Therefore, the upper portion of FIG. 1 illustrates cireuitry which can also be regarded as input equipment for the computer system, even though there is no direct and immediate link, but that input equipment prepares the tape. This input system is denoted generally with reference number 20 and includes the following elements.

There is provided a tablet 21 particularly cooperating with a pen 22. As a tip 221 of the pen is particularly brought into proximity to any point on tablet 21, a spark is produced resulting in emanation of a sound wave of steep and recognizable, shock wave like characteristics. In particular, upon touching the tablet with pen tip 221, a switch 222 therein closes to enable production of the spark.

As indicated schematically, sound waves issue from the particular point of engagement of pen tip with the tablet and that sound wave is detected by two microphones 23 and 24. As can be seen from the drawing, though somewhat schematic, the microphone 23 will particularly respond and detect the first sound wave front that has issued from said point of pen tip contact in the direction of the shortest distance between that point of contact and the microphone 23. This direction is representative of the X axis of an (hypothetically) overlaid coordinate system.

A second microphone, 24, will receive particularly the leading edge of the sound wave after it has traveled the shortest distance between the point of pen tip contact in the Y direction. Therefore, the two microphones respond independently to the issued sound wave, and they detect the first point in time of reception of the produced sound wave along X and Y coordinate axes. The outputs of the two microphones are fed to two amplifiers 231 and 241 respectively, and it was found that particularly the first steep half-wave of such a sound wave is very well recognizable and reproducible as an electric signal with a steep bank. Therefore, pulse discriminators and shapers 232 and 242 are provided on the output side of the amplifiers respectively to provide well developed control signals that identify in time the sound wave propogation across tablet 121 in X and Y directions.

The output signals of the two discriminators are used individually to set flip-flops 233 and 243. The flip-flops when reset open a pair of gates, respectively 234 and 244, for receiving additionally clocking signals from a high speed clock 25. As long as the two flip-flops are in the reset state, they provide gating signals that permit the clock signals respectively to pass to two counters 23S and 245. As the two flip-flops are set, due to detection of sound pulses, the counters stop individually at the respective count state arrived at that time.

Pen 22 includes the switch 222, as stated, which switch is closed as soon as the tip 221 is in physical engagement with tablet 21 and pressed down thereon. The switch closing may well be a mechanical motion resulting from physical displacement of the tip within the pen. As a consequence of closing switch 222, a trigger signal is provided to a circuit 26 which triggers or activates a high voltage source 261 connected to the tip 221 of pen 22 and a spark issues. The output of trigger 26 is also fed to a delay circuit 262, and the delayed trigger signal is used to reset flip-flops 233 and 243 and also to reset counters 235 and 245 to count state zero.

It can thus be seen that on contact of the tip 221 of the pen with the tablet, high voltage circuitry is triggered and a spark develops to issue a sound wave. Shortly thereafter, the two flip-flops and the two counters are reset and enabled so that they can begin to count pulses anew. in effect, these two counters count digitally the travel time for the sound waves toward microphones 23 and 24. After the sound wave has reached the microphones, the flip-flops are set and the counters stop. The counters stop of course individually; normally they will stop at different times except in case the point of contact between pen and tablet is at a point wherein X and Y coordinate values are equal.

After the counters have stopped, they hold information which is the digital equivalent of the travel time and can be regarded as defining a pair of X and Y coordinates of the point of contact between pen tip and tablet. Therefore, the counters hold digital representation as to which point on the tablet was touched by the pen. The delay of circuit 262 simply is a correction in the point of origin of that XY system. The microphones are thus not regarded as placed along the respective zero axes of the XY system but somewhat spaced apart therefrom, which simply is a constraint as to the tablet area available. This constraint serves primarily for suppression of errors; points should not be placed too close to any of the microphones.

As soon as both of the flip-flops are in the set state the content of the counters as holding the X and Y coordinate values of the location pointed to by the pen, can be transferred. An AND gate 27 responds to the set state of both flip-flops indicating that an XY coordinate pair has been detected by the tablet-pen arrangement. The same signal can also be used to effect transfer of these coordinates into two buffers 236 and 246, rendering these digital signals available on busses 237 and 247 while permitting reuse of the counters.

There is now provided a paper punch apparatus 228 which, in response to the signal 27, causes the two coordinate values to be sequentially recorded through appropriate hole punching in the paper tape 17. In essence, the paper punch provides a plurality of hole tracks, some for containing control bits, others contains data bits. A data frame is defined by all bits placed in parallel across the tracks, one bit per track, whereby a hole may represent a bit of value one" and absence of a hole represents a bit of value "zero." Typically there will be five data bits per frame, a parity bit and two additional control bits.

Each of the X and Y coordinates may be represented by 10 bits for a resolution ofone part in (2" l on the tablet and each coordinate will be recorded at two sequential frames of five bits each. The recording process may thus involve calling first on the five high order X bits as held in register 236, then the five low order X bits are recorded, followed by five high order Y bits in the third frame, and finally the five low order Y bits are recorded on the last frame. The first frame as having five data bits may be accompanied by a control bit in one of the control tracks for marking the beginning of a set of four frames for a pair of XY coordinates.

It is that tape 17 which is read by the tape reader 16 within the system. Paper punching and paper reading may well occur at entirely different phases of operation and at different times and/or different locations. It is readily understood that, in principle, busses 237 and 247, could be interfaced directly with the computer 10, operating, for example, on a time-sharing basis, with the output of the gate 27 serving as computer interlock to directly load the content of registers 236 and 246 into the computer memory. This, however, is quite impractical; using a punched tape as intermediary is more economical than a direct link. Moreover, the tape serves as a permanent record. Nevertheless, the device 20 must be regarded as a peripheral device of the computer. This peripheral device 20 provides a data stream recorded, for example, on punched tape. The data stream comprises a sequence of sets of frames, four frames per set, and each set representing a pair of XY coordinates identifying a point on the tablet that has been pointed to by means of pen 22.

The computer system processes and interprets this data in accordance with programming. That interpretation will be defined later in the specification. A particular example of the type of interpretation required for operation of the system will now be explained with reference to FIG. 2.

TABLET AREA FIG. 2 is a more detailed representation of tablet 21 as a working area in which each point is merely characterized by a pair of XY coordinates that could be assigned to such a point through a coordinate overlay for an entire tablet and as actually generated by the spark producing, sound pickup and counting devices explained above with reference to the subsystem 20. It should be mentioned that this kind of tablet and this kind of coordinate generation is described only by way of example and it is equally possible to use other kinds of translators as between the designation of a point in an area and the generation of digital interpretation and representation thereof.

The tablet, in a typical case, is now hypothetically divided into three areas. The first area is defined in parts by tablet boundaries and by the tablet area to the left of a coordinate line X1. That line may be drawn on the tablet to facilitate use. This particular area is in the following called the plan area and is characterized by the fact that any point in plan area recorded on strip 17 is being given an interpretation of geometric significance, but only through processing. In particular, the spatial relation between two or more designated plan points is to have significance corresponding to the geometric relation between these points on the tablet. Typically, two points are to designate a distance, i.e., the end points of a line. As will be explained more fully below, the presentation of a pair of coordinates in that plan area will lead in the computer, upon processing, to an identification of these coordinates directly as a geometric or location descriptor, and through processing the coordinate values are associated with a geometric or location descriptor identification code.

The area to the right of the X1 line and above a Y1 dividing line will in the following be called the descriptive overlay area. Points in the descriptive overlay area are used to identify what in the following will be called quality descriptors. Whenever a point in the descriptive overlay area is pointed to by the pen, it is interpreted as a call for a particular descriptive quality. The quality is represented by a descriptor code, and a representation thereof is associated with the coordinate pair of that point within the file and memory system of the computer, so that the coordinates of that point when called by the pen and recorded on tape, can be used internally in the computer to call for the particular quality code. The coordinate values themselves are not made part of the descriptor identification, but are dropped once the association has been made.

The user of the tablet will be provided with a particular descriptive overlay, such as overlay 211. A more detailed example of such an overlay will be described more fully below with reference to FIG. 2A. On that overlay, the user will find specific quality designations and descriptor descriptions next to small areas such as circles 212, provided to encircle the descriptor points on the overlay. The user is instructed to place the overlay in the area above Y1 and to the right of X1. Upon touching an encircled point 212 by means of the tip of the pen, the X and Y coordinates thereof will be recorded and thereby that particular quality is preliminarily identified. The encoded representation of that quality is held within the file system of the computer in association with that pair of coordinates, and upon processing the tape by the computer the code will be assembled for further use.

One can, for example, make the following distinction among quality descriptors: a general qualitative descriptor, a quantitative descriptor with implied particular quantitative value or values, a descriptor that requires additional, quantitative information not implied, and control descriptors. A general, qualitative descriptor is merely identified by a code selected from within the range for all qualitative descriptor codes. The quantitative descriptors are identified by codes taken from a different range and the quantity values used for the respective descriptors are attached to the respective code for description and the attachment results from computer processing. Control descriptors are identified by codes, as such, but are treated on an individual basis. In neither case, however, are the descriptive overlay area coordinates of a descriptive point part of the code assembly; the overlay coordinates merely identify associatively the descriptor called for when the pen has touched the particular point.

By way of example, a general qualitative descriptor is used to identify particular objects, usually in conjunction with points in the plan area, delineating or identifying relative location of such an object. A descriptor with implied quantity includes a code which will be used to identify an object in conjunction with particular dimensions thereon. A quantitative descriptor without implied quantity is similar as to object identification, but it requires the value of the quantity or quantities to be supplied in addition. The manner of supplying such quantitative descriptors will be explained next.

The means for providing any quantitative information is the "keyboard" generated also on the tablet through use of an overlay. The particular area below line Y1 and also to the right of line X1 is designated the keyboard area. A special overlay 213 is to be placed onto and within that area of tablet 21. The keyboard overlay bears only circles 214 which together in effect illustrate a regular, normal keyboard. When so placed into the keyboard area of the tablet, the user simply uses the pen to touch the pictorial representation of the key; thereby he generates a pair of XY coordinates, to be recorded on tape 17, and software in the computer will interpret the recorded XY coordinate pair, when in the keyboard area, for example, as a digital number descriptor just as if that particular digit had been keyed in with a regular keyboard. Also, the processor will generate a number descriptor code and attach the same to the "keyboard" digit that is associated in memory with representation of the coordinate pair of the point in the keyboard area that has been touched.

As a matter of convenience, the keyboard area could also contain some qualitative and/or quantitative and/or control descriptors having immediate relation only to the keyboard. Particular circles here may define points associated with codes or numbers for defining dimensions of a number keyed-in and representing, for example, inches, feet, dollars, etc. Also, the keyboard overlay may have an END-OF-ENTRY key." The keyboard area may additionally include circles around points associated with letters to complete the keyboard area for a complete alpha-numerical keyboard. In particular, a portion of the keyboard area may literally be a pictorial representation of typewriter keyboard. Upon recording such a coordinate pair and processing, the coordinate pair will be found in memory to be associated with a numerical code that represents a letter of the alphabet or any other symbol. That code will then be associated with a letter descriptor for further processing and data assembly.

it should be mentioned that circles in any of the overlays could be used to identify a point to be associated with generation of control operation. Thus, such points will be associated in the computer with control descriptors. It should also be mentioned, that the differentiation of overlays as different physical elements is only a matter of convenience. There could be a single overlay with descriptor "keys" and alpha numerical character keys." It is the presence of such different keys" that is important per se, therein physical arrangement is dictated by convenience; as there are different descriptive overlays, it is convenient to separate therefrom the one keyboard overlay.

Summarizing the foregoing, the following can be said to be enlarged on later in this specification. Upon touching tablet area 21 anywhere by means of a pen as described, a pair of coordinate values is generated and recorded on tape in four frames. Each coordinate pair is subsequently processed and interpreted as a particular descriptor, having significance by itself as well as in relation to previously and subsequently recorded coordinate pairs generated in the same fashion. The coordinate pair in the plan area will be associated with a location or geometric descriptor identification code. That code is the same for all points in the plan area and may, for example, be digitally represented by the number I401.

A coordinate pair in the descriptive overlay area will be interpreted as quality description particularly as general qualitative descriptor, special or alternative descriptor, quantitative descriptor or control descriptor, and will be associated with a particular qualitative or a particular quantitative or a particular control descriptor identification code, in the following called I- code and found in memory as being associated with the coordinate pair in the overlay area. In cases, the association with such a descriptor code may include digital representation of quantity description or describing numbers, found in memory in association with a particular l-code.

The coordinate pair in the keyboard area will be interpreted as alpha-numerical descriptor to be associated through processing with a generated number descriptor code or a letter descriptor code, as the case may be. Each such code will then be associated with digital representation of a particular number or of a particular letter code and numbers representing the value of the number or inside the letter. Sequences of coordinate pairs generated by the pen in different areas, and, possibly, in a particular order of sequence, will cause association of descriptor identification codes together with the various descriptions, if any.

The various associations and tablet partitions, etc. are to be understood only as a major convenience and not as strictly exclusionary rules. For example, particular subareas may be set aside anywhere on the tablet for placement of particular control descriptors. The two overlays on tablet 21, as depicted in FIG. 2, show additional points marked A, B, C, D, used for purposes of overlay alignment. Whether these points are associated with descriptors as defined above is open to interpretation, they will be treated individually.

Without intending to be restrictive, FIG. 2A illustrates an example for a descriptive overlay whereby it is presumed that the method is used in conjunction with architectural drawings to be placed in the plan area. In other words, it is assumed that the user has placed an architectural drawing on the plan area or is about to design one thereon, including for example floor elevations, etc. Therefore, the points he may touch in the plan area have geometric significance in the sense that they stake out the various parts and corners, etc. of a house including the end points of walls, and points of windows, doors, etc.

Ill

The particular descriptive overlay is used to provide descriptive and other associative information in relation to the drawing. The particular overlay illustrated can be called a walls overlay in that it contains description of descriptors by means of which a wall can be described. Other overlays, for example, may relate to floors, roofs, plumbing, wiring, etc.

An overlay by itself is a flat piece of plastic, cardboard, etc. preferably made of durable material. The operative portion of the overlay consists of circles, such as 212, which define overlay points" in the respective center. Instead of a circle, one could use a square. In any case, the elemental area so marked around a point defines a range of tolerance within which the tip of the pen can be placed and be regarded safely as pointing to the "point" in the center. Processing of the tolerance is part of the input and tape processing program to be described.

Next to each point-defining-circle is written labeling or there is object identifying illustration to inform the user of the meaning of the descriptor attached to such a point. This association is, of course, totally arbitrary and can be chosen in any manner, particularly with primary emphasis on convenience. Overlay definition in that manner is part of the initialization program and will also be described later on as a particular branch of the input program.

Common to all overlays are two points A and B designated by circles or points as described and by means of which the particular position of the overlay, when placed in the overlay area, is defined. The user is instructed always to touch these two points A and B first and that will establish position parameters for that particular overlay. Starting operation in that manner permits corrective association between the points of the overlay as touched and the point coordinates as they are stored in the so-called overlay table as digital data of the computer system. Elaborating on this point, it should be noted that the computer memory is capable of directly associating only particular coordinate points of the overlay area with the particular descriptors and their codes. but the overlay demarcations for these points may not coincide if the overlay had not been placed exactly in a registering position. By marking two points A and B on the overlay, corrective parameters are generated to compensate for such misalignment.

One of the characteristic features of such an overlay is a hierarchy structure of some of the descriptors, particularly of the general qualitative descriptors and we distinguish here between unit descriptors, and item descriptors. Thus, within an extensive input operation, the user will deal with several units." A particular wall is a unit. All units have unit descriptor identification codes within a range, for example, from 1,000 to 1,199. A unit will have several items, for example, windows, doors, or other openings in a wall. Items may have descriptor identification codes in the range, for example, from 1,200 to [,299. Further distinction can be made for such a descriptor point as whether the unit or item it represents is to represent insertion or deletion of the unit or item. Different l-codes can be assigned, one each for insertion and one each for deletion. It can easily be seen, that such hierarchy structure can be developed further if needed.

The walls overlay illustrated in FIG. 2a, is used for all walls in the following manner. Two circles are drawn around points labeled for "insert and delete." The user will touch the point wall insert" first. Upon processing the punched tape, the computer will later interpret the coordinate pairs of this point as associated with the "insert wall" descriptor identification code, for example, 1101. The user is instructed to touch next two points in the plan area which are the corner points of that particular wall. Thereby he defines the position of the wall within the plan area and, particularly within his drawing made. Without further steps, the two points will also define the relative length of the wall.

The circle labeled height" refers to the height descriptor of the wall. The coordinates of that descriptor point are associated in memory with a particularly quantitative descriptor code identifying and related particularly to wall height. lt is convenient to distinguish, for example, between one-number and twonumber descriptors, express or implied. "Wall height" will be a one-number descriptor. A one-number descriptor includes a one number descriptor identification code associated in memory or to be associated additionally with a number value (in addition to association with the point coordinates in the overlay area). That number may have to be keyed in by the user or, for example, in case of height, a standard height value may have been associated already in memory with the wall height descriptor code.

One number descriptor identification codes may, for example, have a value from 1,300 to 1,399, twonumber descriptors may have identification codes between 1,400 and 1,499. Please note that the location descriptor code 1401 falls in that class, because the location code has character of a two-number descriptor. However, the location descriptor does not have to be used on the overlay as a special point. The two numbers are in this case, and only in this case, the two plan coordinates, and the descriptor code is generated as a result of detecting a plan point. Quantitative descriptors as defined on a descriptive overlay have their coordinate representation dropped once the association is made.

It may be assumed that in the particular example, the number value for the wall height is not implied. After having touched the point wall height" in the overlay, the user is instructed to subsequently key-in the value of the height he desires using, of course, for this purpose the keyboard overlay! Upon using the keyboard overlay, he generates separately coordinate pairs, and it is part of the input program to associate the wall height code entry with the particular keyboard entries made thereafter and representing the number that has to be keyed in for the particular one-number descrip tor.

There may be different types of walls which aspect does not have to be discussed in detailythese e.g., standard walls, balloon, gable, or continuous header type walls, etc. Each of them can be regarded as a special type of qualitative descriptor for more particularly describing the wall. These types of qualitative descrip tors (not identifying per se a unit or an item but modifying same) may also be termed alternative descriptors represented by alternative descriptor identifying codes. These codes may be within the range of 2,000 and up. As they are qualitative descriptors, they are only represented by an identification code, without association of additional value numbers in the input system (except for the coordinate points in the overlay area with which they are associated.) Usually, they will lead to particular branch programs for more complex numbers and value sets to be called and included.

In addition, there may be a requirement for particular pitch of the roof (one number descriptor) and there will be different heights on different ends of the wall; overlay points will be provided for each of these possibilities. Another aspect of a wall to be described, particularly in case of a wall for frame houses, is the stud size as well as a stud spacing. There are correspondingly labeled "points in the descriptive overlay. Either descriptor has a quantitative descriptor code, stud spacing has a one-number descriptor [-code, stud size has a two number descriptor l-code, namely for the cross-section dimensions; the height of the stud will result from the wall height.

In either case, stud spacing or stud height, the descriptor values may be implied, i.e., in memory the particular overlay point is found in association not only with the stud size or stud spacing identification codes but also with the respective size and spacing values. Alternatively, it may be required to key-in the particular values of the describing numbers.

For example, the user will first touch the stud size descriptor point in the overlay, which in this case is associated in memory only with the stud size descriptor identification codes. Next he will key-in the two values for width and thickness dimensions for the studs to be used. The height, of course, is determined by the height of the wall and need not be associated with the studs at that instance.

Stud spacing is a one-number descriptor. lf spacing is not implied, it requires the touching of that overlay point whose coordinate pair are associated in memory with the stud spacing descriptor identification code. Subsequently, a number is keyed in by the user and that will give the spacing in between any two neighboring studs on that wall. Upon processing the input, that number will later on be associated with the stud spacing identification code.

As the construction of the wall will depend on whether it is a first or second floor wall or whether the wall is load-bearing, the user will have to touch the appropriate points so designated in the overlay. The codes associated with these points are clearly qualitative, alternative descriptors.

Aside from describing the wall from an overall point of view, the wall as a unit may or may not be provided with certain items, such as doors, windows, fireplaces, etc. Through appropriately circled points of the overlay, insertion or deletion of these items is indicated, followed usually by the keying-in of the location in the plan, followed, in turn, by touching quantitative descriptors calling for door or window height, as the case may be.

It can, thus, be seen that by virtue of a descriptive overlay, plural units (e.g., walls) can be defined within the plan area using the same overlay but sequentially staking out and identifying each such particular wall, describing it, providing it with appropriate items (doors, window, etc.,). Each unit always begins with the keying-in of the unit descriptor point, and then the unit is detailed through insertion of the location of the wall and, possibly, by keying-in additional dimensions and further detailing descriptors, as well as by inclusion of additional items which are more fully described qualitatively as well as quantitatively. Quantitative description refers generally to the location and dimensioning of such unit and item whereby, for example, the location is described in a plan view by means of plan points and height or other dimensions are keyed in numerically. Please note that use of height-descriptors permits the inclusion of dimensions transverse to the plane of the plan area.

in addition, a descriptive overlay will include circles identifying overlay points that are to be associated with particular control descriptors such as reference, skew," end-of-overlay, etc. The latter "point" will be touched for generation of an end-of-overlay code (EOOF) to signal the end of use of a particular overlay. An option should be mentioned here. Each overlay may also be provided with a control descriptor key marked end-of-tape, to signal that further overlays are not used. Alternatively, the tape punch 28 may have a control button included for that purpose. The meaning of the other points will be explained pursuant to description of the program.

From the foregoing, it will have become apparent that the descriptor overlay as well as keyboard overlay in the plan area permit a versatile interplay. Geometric configurations are described and more particularized through the use of the overlays. However, at this point, the dimensions staked out in the plan area are limited to the accuracy of pointing to the plan area. It is also possible, as will be developed pursuant to program description below, to have two geometric points in the plan area scaled to a much greater accuracy than possible by way of pen pointing, simply by keying-in, subsequently to pointing to two points in the plan area, a number having any desired degree of resolution, and that number will be used to correct the coordinate values of the plan points so that they assume the distance relation exactly as keyed-in and at a greater accuracy possible than by pen pointing alone.

Another point to be made is that the various descriptor overlays each use the same overlay area and possibly the same points therein. The distinction comes from overlay identification, which causes the various points in the overlay area to be associated with descriptors in a new and different association and correlation for each overlay.

DATA FORMAT AND STORAGE Before proceeding to the description of particular input program by means of which the tablet inputs are appropriately processed, some remarks are necessary concerning the format of data as well as of relevant storage facilities.

As stated above, the punched tape 17 is provided with a sequence of digital representation of coordinate pairs, each representing a point in the tablet that has been touched by the pen 22. These X and Y coordinates are presented in four sequential frames, two frames defining digitally the X coordinate word and the next two frames defining the Y coordinate word. The two words or four frames are to be identified by a control marker such as 171 and it will be explained more fully below that, upon reading, the tape reader 16 is controlled to step from position to position as marked by the control markers while reading the four frames in one reading step.

The disc memory 15 includes a number of files with each file containing particular data in a form at that can be described as serial-by-word. A typical word is a descriptor identification code (an l-code), as outlined above, other word are the X coordinates and the Y coordinates (one word each); still other words are describing numbers, each up to the limit of the word format range which may be 2" for a 16-bit word format. Particulars of the storage format per se are not important.

One of the files is called the master file 153. Actually the master file may be divided into "old" and "new" master files, but this distinction is not relevant for explaining the invention. It need only to be explained that in the master file there is accumulated the output of the input program, i.e., there is accumulated the interpreted sequence of pen-tablet interaction. The old master file will hold the completed data while the new master file is used to accumulate completed interpretations of one overlay after the other. Such an output file usually beginning with a unit identification code, is a sequence of words. Generally, a descriptor identification code or 1 code is followed either by another l-code or by a descriptive number, or by a pair of processed X- Y coordinates if the l-code was the location descriptor. Such a descriptive number is either followed by another or by an l-code; a coordinate pair will always be followed by another l-code.

The file 154 is called ascratch file and is used for accumulation and step by step buildup of the interpreted coordinate pairs as recorded on tape. Again, the scratch file may be divided into new and old files which is inconsequential for the invention. It is merely a matter of programming convenience to update a scratch file by swapping information between two scratch files. The data format in the scratch file is similar to that of the master file.

The file 155 is called the overlay file. Generation of the overlay file will be explained below. Suffice is to say presently that it is a file which includes several group of words or word sets. The complete overlay file can be divided into a number of files, each one associated with one particular descriptive overlay. The file for one descriptive overlay contains a plurality of word sets and each word set is composed and has a format as can be seen best from FIG. la.

A word set has a pair of coordinate words X and Y, for example, which define a particular point within the overlay area of tablet 21. These are the points of the tablet which will register with the center of circled areas 212 provided the overlay has been placed properly and in strict registration with the tablet points. However, it was mentioned above that points A and B on an overlay serve for alignment correction. This detail does not have to be considered presently.

In a typical case, at least one, more often two or three, related codes are associated with such a coordinate pair of the overlay table. One of the codes is always the particular descriptor identification code or code. Thus, it is this file which provides for the association between descriptive overlay points and descriptor identification by means of digital signals. Such a file, when copied into memory, establishes an overlay correlation table to be used for interpreting tablet points as descriptors. Note, that the different overlay files all refer to the same overlay areas, as only one overlay at a time is used.

As outlined above, we distinguish between qualitative, quantitative and control descriptors, and the classes are distinguished by ranges used for the codes. In case of a quantitative descriptor, the codes Nl (one number) or N1 and N2 (two numbers) will be the respective describing numbers themselves unless a special code (2'-2) in such a word position is used to indicate that the particular quantitative value has to be keyed-in. Other variations and utilization of other control numbers near the upper end of the range (2",) are used, as will become apparent more fully below.

The first one of these word sets for a particular overlay file is preceeded by the identification code for identifying that particular overlay. That overlay identifying code need not be associated with an X-Y coordinate pair in the overlay area, though such possibility should not be excluded. Another particular identification code in an overlay file is used to mark the end of an overlay file to distinguish that file from others in the complete overlay file 155.

The so-called keyboard file 156 is actually part of the complete overlay file but is reasonably considered to be a distinctive entity. The keyboard file is also composed of such word sets, i.e., there are plural pairs of X and Y coordinate words defining points within the keyboard area (see FIG. 111). Each of such pairs is associated with a code representing, for example, the digital value of the keys" as defined in the corresponding keyboard overlay as associated with that pair of coordinates. The code may actually be a binary equivalent of any number 0 through 9.

In addition, the keyboard may include symbols and letters, and they are represented by basically arbitrarily selected respective codes. Finally, the keyboard area will include particular keys" associated with control descriptors. Such keys" are represented by particular XY coordinate values for the center of a pictorial representation on the keyboard overlay when placed in the keyboard area control keys" are, for example, end-of-entry" or dimensional control keys implying, for example, that arithmetic has to be performed to obtain consistent scaling and dimensioning.

For example, all dimensions which may be keyed-in may be understood normally in units of one-eighth inch. A special "key" may denote inches" requiring the preceding number to be multiplied by eight. Another key may be the key for control descriptor feet" which indicates that the number previously keyed-in is dimension in feet. Therefore, upon pressing such a key there will be an implied multiplication by 12 followed by a multiplication by eight.

In all these cases, it has to be pointed out that an XY coordinate pair from the keyboard area is associated in the keyboard file with particular key value or key value defining codes. Particular descriptor identification codes are not part of the keyboard file as number and letter descriptor codes are generated separately. It will be recalled that the number and letter descriptor codes are the same for all numbers and for all letters respectively. Additionally, it should be pointed out, that the X-Y coordinates of the keyboard file refer to such coordinates in the keyboard area. These points are identified by a keyboard overlay. ldeally, the overlay is placed in precisely registering and aligning positions. However, for correcting misalignment, the points G0 are provided on the overlay to be used for obtaining software misalignment correction.

The computer memory 12 includes, of course, conventional circuitry and considerable portions thereof will be used and dedicated for compiling regular computer operation. Also, of course, this system may be used on a time-sharing basis so that various programs may be resident in memory. For the execution of the input program and for evaluating and interpreting the several coordinate points as presented to the tape reader 16 by the tape 17, certain areas and portions within the core memory are needed and have significance in the description of the program below. To a description of these special memory portions and areas, we now turn.

First of all, there are the current "overlay table" and the keyboard table. The overlay table holds the entire content of one particular overlay file which has been identified previously and was caused to be copied from disc file into core memory. It is convenient to define a word set location, which includes the X and Y coordinate values as locations of a descriptor in the overlay area, the descriptor l-code being associated with that overlay area point and with describing numbers, if any. The "keyboard table" is just the entire keyboard file copied into core memory.

Next there is the Loom table. The content of the 1- core table is built up, step by step, as all data related to a unit are accumulated therein. Prior to processing the data of the next unit, the lcore table content is transferred to scratch file 154. Usually, this l-core table begins with the identification descriptor code for a particular unit, and data related to that unit are accumulated in the l-core table until processing encounters the l-code of another unit. The current entry in the l-core table is identified by an I-core pointer which actually is a number defining core memory address for the next entry to be made in the core table. An END-OF-UNIT (EOUF) marker code demarks the other end of the core table as filled thus far. EOUF does not demark the end of the core memory portion available as core table.

Another portion of the core memory is set aside as the so-called Q register for temporary storage of the code and of all related codes and numbers found in the overlay table presently resident in core memory under that designation in association in the a coordinate pair of a descriptor point. A Q-pointer identifies a location for the current entry in the Q register. In the following we will distinguish between 01, Q2, 03 etc. register portions, each such portion permitting storage of one word. An lQ register is used analogously but by different program routines. The front section of the 10 register is called the l-code section which holds a descriptor identification code; the describing numbers are set into additional sections of that register. A pointer identifies the current entry in the lQ register. An N register with pointer is used to accumulate multiple numbers, a CM-register with pointer is used to accumulate letter strings.

A plan point table" identifies all location points in the plan area 215 (plan points) that have been used in conjunction with an input operation. Plan points are defined by coordinate values in this table stored therein, at maximum desired accuracy and in consideration of scaling operations, supplementing dimensions, etc. Each such point so entered is associated with a counter" which is a word location in memory associated with a particular plan point that has been entered; such counter" location holds a number representing the number of uses a point has been made of.

A point array table is a working area in memory used in the stepwise process of obtaining increasing accuracy in the geometric relation among the several points, prior to insertion in the plan point table. Also, each point so processed will be set into the l-core table, the coordinates being the two numbers that describe the two numbers and location descriptor 1401. No such descriptor code is needed in the point array table or in the plan point table. The two point tables, of course, each are associated with pointers for control of current entry.

INPUT PROGRAM FIRST PART We now proceed to the description of the program used to process the information on strip 17. It is repeated that this strip contains only digital representation of coordinate pairs of points touched on table 21 by pen 20. However, the user who has prepared the tape by means of suitable overlays, is instructed to proceed in a particular manner. Particularly, he has to touch points in various areas in particular sequence, and he has to begin such operation in a particular manner. In the following description we shall refer repeatedly to these user instructions upon describing processing of information particularly on basis, what particular coordinate points are expected to have been recorded next on the tape. The program is described on basis of flow charts, summarizing the essential parts of the program. A print-out of the Fortran statements of the complete input program is appended to this specification.

The main program sequence is illustrated in three FlGS., 3a, 3b, and M. We turn first to FIG. 3a. The main program is begun through entry statement or box 300 referring to the initial setup which includes the usual assignment and the initial setting of flags, definition of file, registers, etc. After the initialization the program shifts to box 301, and a card will be read by the card reader 18. This is conventional computer operation for determining the mode of operation. For purposes of this program we distinguish the following three modes which are listed in their order of normal use.

The first mode is the keyboard define mode, used to define the keyboard on tablet 21. During any mode a keyboard overlay is placed in the keyboard area but in the keyboard define mode the keys" are identified both as to their location on the suitably placed keyboard overlay and to what the keys are to represent. The process, therefore, involves particularly the generation of the keyboard table (FIG. lb) and its transfer into the keyboard file 156.

The second mode is the so-called overlay define mode in which encircled descriptor points in a descriptor overlay as placed in the overlay area are identified (l )as points in the overlay area, and (2) such points are additionally associated with related codes under utilization of the keyboard which must have been defined at that time. In particular during this mode, overlay points are defined and the relevant codes for establishing each point as a point are keyed in. Thus during the overlay define mode an overlay table (FIG. la) is generated as to coordinate point-code association.

Of course these two modes, the keyboard define mode and the overlay mode both have their counterpart in operator use, and the computer program mode in the strictest sense involves only the processing of that use. In other words, the content of the tape during these modes includes information only as to the keyboard table and overlay table generation without involvement of the plan area.

The third mode is the normal mode or operate mode. This mode is used only if there is at least one overlay on file in the computer system and if the keyboard is already defined and also on file in the computer system. On basis of these files and in conjunction with the particular overlay properly placed in the descriptive ove-rlay area and in the keyboard overlay area, the user can now use in addition the plan area, and in conjunction with these overlays points of geometric significance have been touched by the user. In the normal mode these various related entries in plan area, keyboard area and overlay area are processed.

Upon running the program, a card will have been put into the card reader to define the mode and as per box 301 the mode flag is set correspondingly. However, regardless of the mode as so selected, a previously prepared tape as it will now be read by the tape reader in steps, and as determined by the program is begun under particular rules. The user knows that at the beginning of preparing such a tape points he touches have a very definite meaning for initialization operation or setup. it is not necessary to describe that in case of error i.e., in case of failure to observe these rules, the program will include provisions to branch into a trap routine to deal with the situation accordingly.

The user rules to be observed in the beginning, are the following:

Upon placement of a descriptor overlay as well as of the keyboard overlay in the appropriate areas on the tablet, the two points A and B so marked on the descriptor overlay have to be touched, in that sequence, followed by touching of the points C and D so marked on the keyboard overlay. This way the exact location and placement of these two overlays is indicated. Therefore, the first four coordinate pairs recorded are then four points. This holds true regardless of the mode.

The program, after having established the mode, enters into a routine identified by PTXY or "read the X and Y coordinates of a point from tape." As tape reading is used generally in computers, no further details are needed here. This subroutine will be called for in any tape reading input operation. Each time PTXY is called the paper tape is stepped through four frames (as marked by control marker 17]) to read the two words for each of the two coordinates X and Y from paper strip l7. The PTXY routine returns the two X and Y coordinates. Presently then, the first PTXY subroutine returns the coordinates of point A. The program proceeds immediately through another PTXY routine to acquire the coordinates of point B. By means of these two points, the physical orientation of the descriptor overlay is being established for further use.

As part of the initial setup, the coordinates of two reference points that can be called A and B are pro vided. All descriptor overlay points and coordinates are to have a particular reference to these points. Ideally an overlay is placed upon tablet 21 with its points A and B in precise registry with points that could be identified by A* and B on the tablet. However, an overlay will only approximately have such a normal position. Usually it must be expected that the overlay is misaligned relative to that normal position. This is now made evident by an apparent deviation between the coordinates of points A and B as they were entered in the tablet and as now read from the tape, on one hand, and the coordinates of reference points A and B as stored in the computer. The latter coordinates can also be called the normalized A and B coordinates.

Therefore box 303 refers to calculations carried out for establishing a matrix which defines correction values. Each point subsequently touched in the overlay area will have its coordinates corrected to be referenced to the normalized coordinate points A and B. One will particularly see the importance here if one realizes that the same overlay will be used several times but not in immediate sequence i.e., for each such use the overlay may be placed in the overlay area anew. This includes even the first use of such overlay in the overlay define mode. In each case then the overlay will not have exactly the same position as before. Now, with the introduction of this correction matrix, the point positions are normalized and referenced to points A and 8*. For each new placement of the descriptor overlay in the overlay area, a new correction matrix is calculated accordingly, as each time points A and B will be different.

Having calculated the correction matrix, the program proceeds twice through the PTXY routine to read the coordinates of points C and D. These two points establish analogously the position of the keyboard overlay in the keyboard overlay area. Analogously then, in box 304 a second matrix of coordinate correction values is calculated to normalize keyboard inputs relative to initially store coordinates for reference points C and D". The calculated matrix represents alignment errors or misalignment of the keyboard overlay relative to a normalized position.

At inquiry box 305, it is determined whether the program runs in the keyboard define mode. If so, a subroutine called TAPE will be called. Pursuant to that routine plural coordinate pairs will be read from the tape and interpreted to define the keyboard table. This will be explained more fully below with reference to FIG. 5. The TAPE routine is generally designated by reference numeral 420. The number in parenthesis thereafter designates the different places in the several routine and branches of the program where TAPE may be called as a subroutine. Presently, therefore, this is identified as 420(2). At the end of that subroutine TAPE, the keyboard is defined and the keyboard table is copied into the disc file (box 306) to establish therein the keyboard file 156. The system for example may shift automatically into the overlay define mode thereafter. If the program did not run in the keyboard define mode the program loops around the TAPE routine 420(2).

Next in the program a routine NUM is called details of which will be described more fully with reference to FIG. 6. As a result of executing the NUM routine 470 at position 470(l)and as subroutine within the main program, a number is returned that is the keyed-in number identifying a particular overlay that is being used or is about to be defined. Thus, as the user has prepared a tape for purposes other than keyboarddefine, and after he has touched points A, B, C and D on the tables, he was instructed to subsequently key-in the overlay identification number.

If the system is in the overlay define mode, the program branches pursuant to the inquiry at 307 and along the affirmative answer branch thereof to call TAPE 420(3). Upon executing TAPE in the overlay define mode, the tape content thereafter is interpreted as defining an overlay. After completion thereof the program will stop. The details of the overlay define operation will also be described fully below, as part of the description of the TAPE routine.

If the overlay already has been defined, then the system is in the normal mode (or has to be placed in the normal mode) so that the keyed in number identifying a particular overlay returned by NUM 470(1) (following the keying in of A, B, C and D) is used to control a transfer operation (box 309) according to which the computer searches through the disc file portion to find the particularly identified overlay file. If the computer does not find that overlay file, of course the operation stops as an error situation is present. After the file has been found, the file is transferred to core memory to become resident therein as the overlay table. This table is as assembly of word-sets (see FIG. la). Each word set has a pair of X and Y coordinate words associated with one or several codes such as a descriptor identification code, or I code for short and describing or control numbers associated therewith.

Having set up the overlay table in core memory as per box 309, the program inquires whether a new master file has to be set up (310). This will be the case if a new object was placed in the plan area and an entirely new operation is begun. The master file is the one in which the result of the input program is accumulated. It may however be the case that the program currently executed is a continuation of a program that has been begun previously and was interrupted for any reason, or a different overlay may have been used and now the user returns to the original overlay and continues. Nevertheless it is assumed that the same object in the plan area is being described as part of this operation. In this case then, a new master file does not have to be set up. Depending upon the outcome of the test a new master file is or is not set up depending on suitable flag setting.

Again we have to refer temporarily to user instruc tions as to rules to be observed during preparation of tape 17. The user is instructed that, after having keyed in the number identifying the overlay to be used, he must define a point of origin in the plan area (E) and to place a second point in plan area, F, in particular relation to point E to define a normal direction EF, at least approximately along the X axis in the plan area. All coordinates in the plan area will later on be corrected and transformed so that the user can assume for his purposes that the direction EF does define the direction of the X axis with E being the point of origin. By implication he can assume also that his" Y axis will be precisely normal to that direction EF. Additionally, the points EF together establish a distance in the plan area, which as a distance is to be associated with a particular scale value. Therefore, the user is instructed, subsequently to pointing to the point that is to become the point F, to key in a number that will be used as a scale, i.e., the number he now keys in will define the value of distance BE in feet, inches, yards, miles, microinches, etc.

By way of example, the user may place plan point P precisely l-inch from point E, and then he keys-in "1" -"0"-inches" to establish that the drawing he is about to particulariu in the plan area is to be understood in a 1002i scale. Later on, all coordinates in the plan area will be transformed with E as a new zero point of origin, and all coordinates will be transformed further and given values on basis of that scale so that all geometric locations within the plan area are sealed in relations to the value of distance EF.

Returning now to the program execution (beyond box 311), the program calls PTXY again for reading the pair of coordinates on tape that is expected to define E. As per box 312, these coordinates are called lOX and lOY and will now define the new 0 point. [OK and IOY will be used to obtain transformation of all subsequently detected plan point coordinates. Subroutine PTXY is called again to read the next pair of coordinates, which are point P.

As per box 313, angular correction factors are calculated, such as sine, co-sine, etc. representing the deviation of line EF from the X-axis inherent in tablet 2] operation due to microphone positioning therein. It can readily be seen that e.g., any misalignment of the microphones or any other position error sources will be eliminated by defining in that manner a user X axis." All plan coordinates will be angle-corrected on that basis.

Next, the routine TAPE is called again as per 420(4) and TAPE will return the scale number that has been keyed in. Box 315 now refers to the setting up of the scale factor, normalizing the keyed-in distance value as between E and F by recalculating the X-coordinate value of F (E is "0") as representing that distance, and by calculating the scale further (BE in the plan area does not have to be I inch!) the other plan points will subsequently have their X and Y coordinates recalculated on basis of that factor in case the present program is a continuation of the previous one which was interrupted for any reason, the previously completed portion held on the master file is then brought into the scratch file and is also rearranged within the master file as per 316. in case ofa completely new operation, box 316 is bypassed. In any event, the program now arrives at point 317. Having arrived at point 317, the basic setup operations have been completed. The following portions of the program relate to the stepwise acquisition and interpretation of the various coordinate pairs read subsequently from tape. The processing of these coordinates is carried out through several interrelated loops. However, it is advisable to interrupt the description of the main program at the present time and to turn to the description of several salient routines and subroutines including the ones briefly mentioned above. it is also advisable to describe as part of the subroutines the keyboard define mode and the overlay define mode and after having described these modes we shall return to the continuation of the main program beyond point 317.

ROUTINES "READ", "TAPE" AND NUM" We will now proceed with the description of several salient routines and subroutines. 0f basic significance here is the so-called READ routine which includes several subroutines to be described in parts. The READ routine is outlined in FIG. 4. [t is a principal instrumentality by means of which an I code together with associated describing and/or control numbers is taken from a designated source and returned to the program or routine that called for the READ routine. Thus, READ will always return a complete word set. The calling program will either call for READ-tape or for READ-core-memory or for READ-disc. The READ- tape part of that routine is the principal instrumentality for a sequential acquisition and processing of coordinate points of the paper tape. Reading proper is always just carried out by PTXY.

The READ routine as a whole is identified by a reference numeral 400', that number is used as entry point for the routine in FIG. 4. As READ is entered, the first performance is per block, box or statement 401 and involves the determination of the source from which a word set is to be taken. As stated, three different sources can be designated upon calling for the READ routine and we will refer specifically now to the various sources from which a word set is to be taken. As per box 401, the branch is determined along which this routine has to proceed in order to obtain the data from the designated source.

Assuming the source is designated as the tape, then the routine calls for TAPE as subroutine 420(1) to be described in detail later with reference to FIG. 5. Briefly, TAPE 420 (I) will cause the next coordinate pair to be read from tape (unless already read but not processed) and these coordinate pairs will be interpreted, possibly under utilization of the current overlay table and the keyboard table. Usually a descriptor identification word code will be returned upon completion of execution of TAPE. The return statement 402 acknowledges that now an I code has been returned and is stored in the code section of the IQ register. The identification code returned may be the location descriptor code 1401 or any of the other types of descriptors introduced above.

A similar return is provided if the designated source for the execution of the READ routine is the disc file. in this case, a subroutine disc is executed but does not require description. As a consequence of executing DISC, an identification code will be returned from the designated disc file set in the 1 code section of the IQ register. A third branch is the MEM subroutine, block 404 and simply means that from the l core table the final word of a word set (again, normally, the l-code) is being taken out of the word set location as designated by the pointer for the l-core table (See FIG. 1c). Additionally, the pointer will be reset thereafter to point to the next word in the same word set location.

The word that is being returned as per 402, is usually a descriptor l-code. As per box 405 it is tested whether or not it is an I-code other than a control descriptor. If not, box 406 tests as to presence of a control descriptor code. If likewise not a control descriptor, a flag is set as per box 407 accordingly and the routine exits. However, such is not the case normally, as the READ routine is usually called under conditions that the return of a descriptor identification code can be expected.

If the descriptor identification code is not a control descriptor, it may be a qualitative or a quantitative descriptor. If it is a qualitative descriptor, the code returned may be an item or a unit identification code (general descriptor) or an alternative descriptor. The type of descriptor other than a control descriptor is determined as per box 408 and in case of a qualitative descriptor, a flag is set as per box 413. The 1 code or the descriptor is already in the l code section of the register and the routine exits.

The situation is different if the descriptor code is determined as being a quantitative descriptor. If a onenumber descriptor code had been returned, block 409 interrogates where the descriptor number is. Usually, but not necessarily, it will be in the same source from which the descriptor identification code had been take. This means that if the descriptor identification code was returned from DISC, the number associated with the descriptor code will also be on the disc and it will in fact be the next word thereon. The DlSC routine is called again, as per box 410, and will return the next word from the disc. If the describing number is in the next location in the l-core table (next to the one from which the l-code returned previously was taken), that number will be taken out as per block 411, the pointer will be reset, etc.

The descriptor code returned as the result of tape reading can be expected to have the describing number neither in the file nor in the l-core table. Also, the describing number itself is not on the tape as the tape itself does not hold any codes. Instead, the describing number will be held in Q2 location of the Q register and will therefore, as per box 412, be taken from there. In either case, the three branches 411, 410 and 412 will return to box 413 where the completion of assembly of the words pertaining to a word set is affirmed. Presently, a one number descriptor was considered, so that completion of assembly is affirmed when the register holds the l-code of the descriptor and the one describing number.

In case the descriptor code that was returned, as per 402, is a two-number descriptor l-code, the two numbers will be fetched and taken out of memory or from disc (boxes 415, 414) as the case may be. This is analogous to the operation performed under 410 and 411. In case the two number descriptor code originated through tape reading, box 416 requires the first number to be taken from the Q2 register portion, the O register pointer is incremented (box 417) and the second number is taken from Q3. The assembly is completed as per box 413 when the two number descriptor code with the two describing numbers is held in the 10 register, whereupon the READ routine exits.

In case a special control code is returned on 402 to the [Q register, there are different cases possible. Often, the code stands alone, so that appropriate flag setting as per 413 suffices, the code is already in the 1- code section of the [Q register. One special control code that may be returned on 402 is the end-of-file marker, in which case a special flag is set, box 494. The number identification code is of separate interest. This number identification code is generated when a coordinate pair on tape is recognized as a point in the keyboard area. Therefore, if, as per box 492, that special number descriptor is detected as having been set in the I-code section of the IQ register. The number value itself is taken from O2 register (box 493) and is also set into the IQ register pursuant to assembly step 413.

The operation is analogous if the code returned is the letter descriptor in which case the string of letter codes is transferred from the CM register to the [Q register. Note that the letter descriptor l-code (l8) identifies the digital data appended to it as (individual) letter defining codes. Other control codes may be recognized as such and result in particular flag settings (495); among them is the special delete" code 3; the skew" code, the "reference point code. These will be described fully below. All of them may only be recognized summarily, there is no need for further distinction at this point in the program.

it can thus be seen that the READ routine will return an l-code in a section of like designation in the 10 register and there may or may not be associated describing numbers depending upon the type of l-code that is being returned. in case of the location descriptor code, the numbers returned in the two other sections of the lQ-register will be the plan coordinates, properly scaled and dimensioned, but not related to other plan points. In case of a number descriptor, the number code (2) or letter code (18) together with the digital value of the number or the several codes of a letter string will be returned. Other control codes and alternative descriptors cause only a return of the l-code and appropriate flag setting. END-OF-FILE is particularly returned by special flag setting.

The TAPE routine to be described next with reference to FIG. 5, is not exclusively used as a subroutine 420(1) within the READ routine of FIG. 4. When TAPE is entered at point 420, at first it is determined (box 421) whether or not four frames constituting a coordinate pair have been read already from the tape, and are held in a suitable buffer that have not yet been processed further. This may occur as often various routines and subroutines require reading of the next coordinate pair from tape in order to determine continuation or exiting from loop operation or any other particular association or lack of it as to previous coordinate pairs read and processed. If such association or rule for continuation cannot be established, such a routine or subroutine will exit at that point leaving the coordinate pair read in buffer without further processing. Thus, if later on the TAPE routine is called, it may be required merely to process and evaluate this pair of coordinates. Whether or not this is so is represented by suitable flag setting.

If it is decided at box 421 that a coordinate pair has not been read, the PTXY subroutine is called. Otherwise, the PTXY subroutine is called. Otherwise, the PTXY subroutine is bypassed. These X and Y coor- 

1. A method for processing signals representing coordinate values of points in a graphic input tablet, using a stored program, digital data processing facility receiving the signals or representation of such signals, the facility having storage means for storing signals to be processed and having processing means to process signals as stored in the storage means, comprising the steps of: generating First representations for generated coordinate values of plan points in a first particular area of said tablet where points within the first particular area are identified as points of geometric significance; generating second representations for generated coordinate values of plan points in a second particular area of the tablet where the points within the second particular area are identified with descriptive codes; generating third representations for generated coordinate values of plan points in a third particular area of the tablet where the points within the third particular area are identified with numerical significances; providing a first data table in the storage means, the first data table having representations associating the coordinate values of particular discrete points in the second particular area of the tablet with descriptive codes which are independent from each other and independent from any incidental geometric relation among the discrete points in the second area; providing a second data table in the storage means, the second data table having representation associating the coordinate values of discrete points in the third particular area of the table with numerical significances which may be independent from each other and are independent of any incidental geometric relation among the points in the third particular area; determining the respective descriptive code or codes from the generated coordinate values of each discrete point in the second particular area and from the first data table; determining the number associated in the second table from the generated coordinate values of each generated point in the third particular area; and associating the determined descriptive codes in order relation to coordinate plan point or points generated in the first particular area of the tablet and in order relation to the generated coordinate values of points in the third particular area of the tablet; associatively processing, in accordance with a particular order of generation of coordinate values of points in the first, second and third particular areas, the number determined from the second table in relation to coordinate representation determined from the first particular area and descriptive code determined from the first table.
 1. A method for processing signals representing coordinate values of points in a graphic input tablet, using a stored program, digital data processing facility receiving the signals or representation of such signals, the facility having storage means for storing signals to be processed and having processing means to process signals as stored in the storage means, comprising the steps of: generating First representations for generated coordinate values of plan points in a first particular area of said tablet where points within the first particular area are identified as points of geometric significance; generating second representations for generated coordinate values of plan points in a second particular area of the tablet where the points within the second particular area are identified with descriptive codes; generating third representations for generated coordinate values of plan points in a third particular area of the tablet where the points within the third particular area are identified with numerical significances; providing a first data table in the storage means, the first data table having representations associating the coordinate values of particular discrete points in the second particular area of the tablet with descriptive codes which are independent from each other and independent from any incidental geometric relation among the discrete points in the second area; providing a second data table in the storage means, the second data table having representation associating the coordinate values of discrete points in the third particular area of the table with numerical significances which may be independent from each other and are independent of any incidental geometric relation among the points in the third particular area; determining the respective descriptive code or codes from the generated coordinate values of each discrete point in the second particular area and from the first data table; determining the number associated in the second table from the generated coordinate values of each generated point in the third particular area; and associating the determined descriptive codes in order relation to coordinate plan point or points generated in the first particular area of the tablet and in order relation to the generated coordinate values of points in the third particular area of the tablet; associatively processing, in accordance with a particular order of generation of coordinate values of points in the first, second and third particular areas, the number determined from the second table in relation to coordinate representation determined from the first particular area and descriptive code determined from the first table.
 2. A method as set forth in claim 1, wherein generated coordinate values of points in the third particular area, succeeding generated coordinate values of a point generated in the second particular area to represent a particular code of a particular class of codes in the first particular table, are processed by appending to the particular code the numbers representing the points generated in the third particular portion of the tablet.
 3. A method as set forth in claim 1, wherein an algorithm is used to process coordinate values of points generated in a particular sequence in the first, second and third areas with at least two points defining in the first area a dimension of an object in a direction transverse to the first area by the distance between two points in one direction in the first area.
 4. Method as in claim 1, including the step of including an algorithm to replace a point generated within a particular distance from the periphery of the first particular area by the coordinates of the point at the particular distance from the periphery of the first particular area and closest to the generated point.
 5. Method as in claim 1, the detecting steps including an algorithm to determine minimum deviation of points generated in the first table in representation of particular descriptive codes from coordinate pairs of points respectively entered at particular discrete positions in the second particular area.
 6. Method as in claim 1, including an algorithm to modify the geometric relation of sequentially generated points in the first area.
 7. A method for processing signals representing coordinate values of points in a graphic input tablet, using a stored prograM, digital data processing facility receiving the signals or representation of such signals, the facility having storage means for storing signals to be processed and having processing means to process signals as stored in the storage means, comprising the steps of: generating first representation for generated coordinate values of plan points in a first area of said tablet identifying the points as points of geometric significance within the first area; providing a first data table in the storage means, having representation associating the coordinate values of particular discrete points in a second area of the tablet, outside of the first area, with descriptive codes, independently from each other and independent from any incidental geometric relation among the points in the second area; detecting the respective descriptive code or codes as associated in the first table with the generated coordinate values of a point in the second area, and associating the detected code or codes in relation to coordinate plan point or points generated in the first area and in particular order relation to the generated coordinate values of points in the second area; providing a second data table in the storage means having representation associating the coordinate values of particular, discrete points in a third area of the table, outside of the first area, with numbers, independent from any incidental geometric relation among the points in the third area; detecting the number associated in the second table with the generated coordinate values of a point in the third area, and associatively processing the number so detected in relation to generated plan point coordinate representation or detected descriptive code, in dependence upon the order of presentation of coordinate values of points in the first, second and third areas, and using an algorithm wherein generated coordinate values of points in the third area, generated in particular order relation to generation of the coordinate values of a pair of plan points, are used to recalculate the coordinate values of at least one of the pair of plan points.
 8. A method for processing signals representing coordinate values of points in a graphic input tablet, using a stored program, digital data processing facility receiving the signals or representation of such signals, the facility having storage means for storing signals to be processed and having processing means to process signals as stored in the storage means, comprising the steps of: generating first representation for generated coordinate values of plan points in a first area of said tablet identifying the points as points of geometric significance within the first area; providing a first data table in the storage means, having representation associating the coordinate values of particular discrete points in a second area of the tablet, outside of the first area, with descriptive codes, independently from each other and independent from any incidental geometric relation among the points in the second area; detecting the respective descriptive code or codes as associated in the first table with the generated coordinate values of a point in the second area, and associating the detected code or codes in relation to coordinate plan point or points generated in the first area and in particular order relation to the generated coordinate values of points in the second area; providing a second data table in the storage means having representation associating the coordinate values of particular, discrete points in a third area of the table, outside of the first area, with numbers, independent from any incidental geometric relation among the points in the third area; detecting the number associated in the second table with the generated coordinate values of a point in the third area, and associatively processing the number so detected in relation to generated plan point coordinate representation or detected descriptive code, in dependence upon tHe order of presentation of coordinate values of points in the first, second and third areas, and using an algorithm operating in response to generation of points in the first and second areas to assemble the coordinate values of a plan point so defined in relation to an object identifying code and quantitative object description numbers taken from the first table and identifying the object to be located at said plan point.
 9. Method as in claim 8, including an algorithm operating in response to additionally generated points in the third area to augment the quantitative description of the object on basis of the second table.
 10. A method of operating a data processing system having a memory in response to data entered and representing coordinate values of points selected in a tablet having characteristics of generating signals representing the coordinate values of the selected points, comprising the steps of: operating a first particular portion of the memory as a correlation table associating particular points in a first particular area of the tablet with codes representing individual numerical values; operating a second particular portion of the memory as a correlation table associating particular points in a second particular area of the tablet within individual description codes; operating a third particular portion of the memory as an accumulation table in which to assemble coordinate values of points entered in a third particular area of the tablet; individually selecting in order particular points in the first, second and third particular areas of the tablet to obtain the generation of the coordinate values of the points selected; and providing a selection of the individual ones of the description codes, numerical values and coordinate values of points in the third area in accordance with an algorithm that depends on the order of selection of points in the first, second and third particular areas on the tablet.
 11. A method as in claim 10, generating the correlation table in the first portion of memory by entering coordinate values in the table in a particular sequence and providing an algorithm that enters codes in association with the entered coordinate values on basis of sequence of entry.
 12. A method as in claim 10, including, generating particular description codes from the correlation table in the second portion of the memory by sequentially associating coordinate values of points entered in the second particular area of the tablet with the content of the correlation table in the first particular area of the tablet on the basis of points entered in the first particular area of the tablet.
 13. The method as in claim 10, preceded by placement of an overlay in at least one of the first and second particular areas of the tablet and entering alignment points in at least a particular one of the first and second particular areas of the tablet to determine the misalignment of the overlay in the particular one of the first and second particular areas of the tablet, the method including an algorithm to correct each point entered in at least the particular one of the first and second particular areas of the tablet in accordance with overlay misalignment before searching for correlation in memory.
 14. The method as in claim 10, the last operating step including forming a program loop to receive sequentially in a preliminary table coordinate values entered in the third particular area of the tablet and correct the coordinate values in the preliminary table in accordance with numbers determined by the operation of the first memory portion upon detection of points entered in the first particular area of the tablet, and exiting from the loop upon encountering entry in the second particular area of the tablet of a point unrelated to the previous entries in the second particular area of the tablet.
 15. A method of processing coordinate values of points entered in a tablet by means of a digital data processing facility, compriSing the steps of: operating a first particular portion of a tablet area as an alphanumerical keyboard by correlating discrete points entered in the first particular portion of the tablet area with keyboard numbers; operating a second particular portion of the tablet as a description board for description codes by correlating discrete points entered in the second particular portion of the tablet area with arbitrarily selected description codes; operating a third particular portion of the tablet area as a graph board for a spatial relationship by storing in the graph board values representing a spatial relationship corresponding to the spatial relationship of points entered in the third particular portion of the tablet area; and correlating keyboard numbers, description codes and graph board points respectively entered into the first, second and third particular portions of the tablet areas by means of an algorithm that operates in dependence upon the order of entry of points in the first, second and third particular portions of the tablet area.
 16. The method as in claim 15, wherein the operation as to the first tablet area is preceded by placement of a keyboard overlay in the first tablet area and keying-in alignment points, the method including calculating corrective values between particular overlay points and coordinate values stored in association with keyboard numbers in the data processing facility.
 17. The method as in claim 15, wherein the operation as to the second tablet area is preceded by placement of a description overlay in the second tablet area and keying-in alignment points, the method including calculating corrective values between particular overlay points and coordinate values stored in association with description coded in the data processing facility.
 18. A method as set forth in claim 15, including the step of providing an algorithm for scaling distances defined by pairs of points entered in the third particular portion of the tablet area on the basis of keyboard numbers resulting from entry of points in the first particular portion of the tablet area.
 19. A method as in claim 15, wherein coordinate values of points are separated in accordance with their entry into the first, second and third particular portions of the tablet area, and the coordinate values of the points entered respectively in the first and second particular portions of the tablet area are correlated with decimal numbers and description codes.
 20. A method as set forth in claim 15, wherein an algorithm is provided to append keyboard numbers to description codes on the basis of a particular sequence of entry of points in the second and first particular portions of the tablet area.
 21. A method as set forth in claim 15, including an algorithm defining the geometric relation of graph board points resulting from entry of points in the third particular portion of the tablet area on the basis of keyboard numbers resulting from points entered in the second particular portion of the tablet area.
 22. A method as in claim 15, including an algorithm correlating a description code resulting from entry of a point in the second particular portion of the tablet area with a keyboard number resulting from subsequent entry of a point or points in the first particular portion of the tablet area. 